Audit on Technical Adequacy, Structured Reporting and Radiation Dose on Voiding Cystourethrography (VCU) in Pediatric Population

Audit on technical adequacy, structured report documentation and radiation dose for VCU examination performed in pediatric population.

VCU remained the gold standard for the evaluation of vesicoureteric reflux (VUR), providing both anatomical and functional evaluation. Besides VUR, it also provides evaluation to the bladder and urethra. Radiographic findings provide lots of prognosticative information besides grading in guiding individualized management ^1,2.

Variation about VCU techniques and reporting qualities does not allow valid comparison of data between individuals and institution¹.

To improve patient safety and to standardize the data obtained, the American Academy of Pediatrics (AAP) Section on Radiology and the AAP Section on Urology created consensus (2016) on how to perform this test¹. The techniques and image adequacy are in line with those suggested by the guideline published jointly by the American Society of Radiology (ACR) and Society of Pediatric Radiology (SPR) (2019), the SPR Safety, Quality of Care, Practice Guidelines and the imaging recommendations by European Society of Pediatric Radiology (ESPR) workgroup (2007) ^2,3,4.

It is important to strike a balance between image quality and radiation dose in order to achieve “As Low As Reasonably Achievable” (ALARA)¹. The International Commission on Radiological Protection (ICRP) published diagnostic reference level regarding VCU in pediatric population⁶. It was stated that variation in patient radiation dose due to incorrect technique is not appropriate⁶. The image quality should be evaluated as part of Diagnostic Reference Level (DRL) process in order to achieve optimization⁶.

On this ground, we aim this audit would optimize both image techniques and radiation dose in pediatric population. And standardized reporting would yield invaluable diagnostic information to facilitate individualized treatment in patients with VUR.

The standard: 

Image Adequacy

1. Pulsed fluoroscopy, last image hold, and fluoroscopic image capture should be used^1,2.
2. The use of more than 1 bladder filling is a common standard^1,2.
3. Preliminary fluoroscopic grab image can be obtained to review osseous structures. If there is abdominal radiograph in preceding 3-6 months available, then it can be omitted^1,2,3,4.
4. Early-filling last-image capture of the bladder to look for intravesical ureterocele or other mass. While further bladder filling occurs, continuous imaging is not necessary^1,2,3,4,5.
5. Oblique radiographs of the full-bladder are obtained to profile each ureterovesical junction in relation to the bladder neck^1,2,3,4,5.
6. Voiding phase image should include the entire urethra with oblique view in male and frontal view in female^1,2,3,4,5.
7. Post-void images of the renal fossae should be obtained to look for residual VUR^1,2,3,4,5.

Standard Reporting

1. Record number of cycle performed and maximal amount of contrast instilled¹.
2. Record any osseous abnormality detected on scout image¹
3. Record any VUR detected¹
4. Record phase of study in which VUR first detected¹.
5. Record highest grading of VUR detected according to International Reflux Study¹.
6. Record insertion of refluxing ureter¹.
7. Record volume of residual bladder contrast post-void¹
8. Record bladder outline¹
9. Record any filling defect within urinary bladder¹
10. Record any abnormal dilatation or stricture of urethra¹.

Radiation Dose

1. The median DRL of the cohort falls below that of United Kingdom DRL of similar age group⁶.

Target: 

1. For image adequacy and structured reporting, 100% of image adequacy and reports for VCU should meet these standards.
2. For radiation dose, the median DRL of the study population should fall below that of UK DRL

Indicators: 

The percentage of fluoroscopic image and reports which adhere to each of the standards.

The median dose-area product (DAP) of the study population will be collected.

Data items to be collected: 

Image Adequacy

1. Are all the images taken pulsed fluoroscopic images, rather than capture images?
2. Is more than one filling cycle performed?
3. Is preliminary image taken (no prior abdominal radiograph in recent 3 to 6 months)?
4. Is early-filling phase image correctly taken?
5. Is late-filling phase image correctly taken?
6. Is voiding phase image correctly taken?
7. Is post-void phase image correctly taken?

Standard Reporting

Documentations on the followings:

1. Number of cycle performed and maximal amount of contrast instilled
2. Any osseous abnormality detected on scout image.
3. Any VUR detected.
4. If there is VUR, the phase of study in which VUR first detected. 
5. If there is VUR, the highest grade according to International Reflux Study.
6. If there is VUR, the insertion of refluxing ureter.
7. The volume of residual bladder contrast post-void.
8. The bladder outline?
9. Any filling defect within urinary bladder?
10. Any abnormal dilatation or stricture of urethra?

Radiation Dose

1. Individual examination DRL will be collected for analysis.

Suggested number: 

Fluoroscopic images of VCU for pediatric population should be collected and reviewed. All cases performed during the preceding twelve months, or the most recent 30 consecutive cases (whichever number is greater). Incomplete or failed examination should be excluded.

1. Publicise the standards for VCU imaging technique and reporting, through in-person departmental radiology meetings and dissemination of written material to radiologists.

2. Create a structured VCU report template for use during electronic report transcription, in order to improve standardisation of reporting items.

3. Re-audit twelve months after intervention, to assess for improvement in practise. Continue the audit spiral, to ensure sustained compliance with the standards.

1. Radiology information system (RIS) to review administrative details and reports.

2. Picture archiving computer system (PACS) to review saved fluoroscopic images.

3. Statistical computer software, such as Microsoft Excel, for recording and analysing data.

1. Frimberger D, Mercado-Deane MG; SECTION ON UROLOGY; SECTION ON RADIOLOGY. Establishing a Standard Protocol for the Voiding Cystourethrography. Pediatrics. 2016 Nov;138(5):e20162590. doi: 10.1542/peds.2016-2590. PMID: 27940792.

2. ACR–SPR PRACTICE PARAMETER FOR THE PERFORMANCE OF FLUOROSCOPIC AND SONOGRAPHIC VOIDING CYSTOURETHROGRAPHY IN CHILDREN; Revised 2019 (Resolution 10)* https://www.acr.org/-/media/ACR/Files/Practice-Parameters/VoidingCysto.pdf?la=en

3. The Society for Pediatric Radiology Performance of VCUG Examinations: Safety, Quality of Care, Practice Guidelines http://www.pedrad.org/Portals/5/Education/PQI/PQI-VCUG%20Template.pdf

4. Fernbach SK, Feinstein KA, Schmidt MB. Pediatric voiding cystourethrography: a pictorial guide. Radiographics. 2000 Jan-Feb;20(1):155-68; discussion 168-71. doi: 10.1148/radiographics.20.1.g00ja12155. PMID: 10682779.

5. Riccabona M, Avni FE, Blickman JG, Dacher JN, Darge K, Lobo ML, Willi U. Imaging recommendations in paediatric uroradiology: minutes of the ESPR workgroup session on urinary tract infection, fetal hydronephrosis, urinary tract ultrasonography and voiding cystourethrography, Barcelona, Spain, June 2007. Pediatr Radiol. 2008 Feb;38(2):138-45. doi: 10.1007/s00247-007-0695-7. Epub 2007 Dec 11. PMID: 18071685.

6. ICRP, 2017. Diagnostic reference levels in medical imaging. ICRP Publication 135. Ann. ICRP 46(1).

Dr. HM Kwok

Co-authors

Dr NY Pan